Screw openers are generally used tools to drive screws. However in the prior art structure, the size of a screw opener is fixed and as a result, it can not fit for various working environments. Thereby there is an eager demand for a novel design which can adjust the size of the screw opener.
In one improvement, the screw opener has a handle and a driving rod. A front end of the handle has an axial hole. The driving rod has a head for driving a screw unit and a rear end which can be receiving within the axial hole of the handle. A buckle unit is installed between the handle and the driving rod. The buckle unit has a buckle portion in the handle and a control portion installed out of the handle. The driving rod has three recesses for buckling the buckle portion of the buckling unit. The driving rod can be buckled to the buckle unit at different recess by pressing the control portion so as to control the length of the driving rod. There are three stages for adjusting the length of the driving rod.
However above mentioned prior art has the following disadvantages There only three stages for adjusting the length of the driving rod. Furthermore, the structure of this prior art is very complicated. It is very difficult in assembly and moreover, the cost is high. Further the buckle unit can not provide a sufficient endurance to the structure. As a result, in operation, the driving rod will possibly be reduced into the axial hole of the handle. All these defects are necessary to be improved.